CN105452893B - The improved triggering based on ECG for magnetic resonance imaging - Google Patents
The improved triggering based on ECG for magnetic resonance imaging Download PDFInfo
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- CN105452893B CN105452893B CN201480044173.1A CN201480044173A CN105452893B CN 105452893 B CN105452893 B CN 105452893B CN 201480044173 A CN201480044173 A CN 201480044173A CN 105452893 B CN105452893 B CN 105452893B
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- 238000002595 magnetic resonance imaging Methods 0.000 title claims description 33
- 239000013598 vector Substances 0.000 claims abstract description 54
- 238000000034 method Methods 0.000 claims abstract description 30
- 238000005259 measurement Methods 0.000 claims abstract description 21
- 230000033001 locomotion Effects 0.000 claims abstract description 19
- 230000000241 respiratory effect Effects 0.000 claims abstract description 19
- 230000001360 synchronised effect Effects 0.000 claims abstract description 14
- 241001465754 Metazoa Species 0.000 claims description 14
- 230000029058 respiratory gaseous exchange Effects 0.000 claims description 9
- 230000007704 transition Effects 0.000 claims description 6
- 238000003384 imaging method Methods 0.000 claims description 4
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
- G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
- G01R33/567—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution gated by physiological signals, i.e. synchronization of acquired MR data with periodical motion of an object of interest, e.g. monitoring or triggering system for cardiac or respiratory gating
- G01R33/5673—Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker
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Abstract
By means of magnetic resonance to the method for the object of interest being positioned in magnetostatic field being at least partly imaged, comprising: obtain the measurement result of the ECG data of object of interest heart；Vectorcardigram data are generated according to ECG data, the electric axis including determining heart；At least one parameter of the acquisition period of collecting magnetic resonance signal is determined according to vectorcardigram data, the measurement result of magnetic resonance signal is synchronous with the cycle movement of the heart of object of interest；At least one parameter of acquisition period is wherein determined by comparing the actual value of discriminant function and predetermined reference function, discriminant function is based on the angular dependence between the electric axis of determining heart and the instantaneous vector of vectorcardigram, the fixed threshold of actual value of the predetermined reference function based on discriminant function, wherein in order to determine acquisition the period at least one parameter, respiratory state based on object of interest executes the step of adjusting at least one in discriminant function and predetermined reference function.
Description
Technical field
The present invention relates at least portions by means of magnetic resonance to the human or animal's object interested being located in magnetostatic field
Divide the method being imaged, and for acquiring the object of interest synchronous with the cycle movement of the heart of object of interest
The magnetic resonance imaging system of at least part of image.
Background technique
In the field for cardiology purpose application MR imaging method, it is known that generally can not be single at one
Magnetic resonance image is acquired during cardiac cycle, but magnetic resonance image is acquired by the repeated acquisition of magnetic resonance signal, wherein
Repeated acquisition is synchronous with the cycle movement of heart.
For example, the repeated acquisition of magnetic resonance signal synchronize can be compound about the QRS- of ECG signal main R- wave
It is implemented, each part to ensure magnetic resonance image is collected in the same phase of cardiac cycle.However, noise source, such as
MHD effect and gradient magnetic distortion, cause stationary problem.
In order to overcome these problems, sentencing by comparing vectorcardigram has been proposed in 0 925 019 B1 of EP
The actual value of other function and predetermined reference function, the vectorcardigram obtained from the measurement according to ECG data is come really
Determine the acquisition period of magnetic resonance imaging system, instantaneous vector of the actual value based on determining heart electric axis and vectorcardigram
Between angular dependence.In one embodiment described in 0 925 019 B1 of EP, discriminant function is defined as vectorcardigram
Instantaneous vector and heart electric axis dot product.Predetermined reference function can be the fixation of the amplitude peak of discriminant function
Threshold value.
US2007/0092123A1 describes the method and apparatus for the motion correction when heart is imaged.Root
According to the vectorcardigram of measurement, the variation in the spatial position of the heart between cardiac cycle is calculated.When the different pictures of combination
When consider variation calculated, to avoid or at least to reduce the error in combined Imagery Data Recording, the error
It is as caused by the variation in the spatial position of heart.
Summary of the invention
It is expected that can be further reduced for determining the further improved method of acquisition period for magnetic resonance imaging
Scanning, particularly for the quantity of the mistake acquisition period of the scanning executed at the out of phase of the breathing of object of interest.
Therefore, the purpose of the present invention is to provide a kind of by means of magnetic resonance to the people interested being located in magnetostatic field or
The improved method of animal target being at least partly imaged.
It the described method comprises the following steps:
Obtain the measurement result of the ECG data of the heart of the object of interest；
Vectorcardigram data, the electric axis including the determination heart are generated according to the ECG data；
At least one parameter of the acquisition period of collecting magnetic resonance signal is determined according to the vectorcardigram data, with
Just the measurement result of magnetic resonance signal is synchronous with the cycle movement of the heart of the object of interest.
Wherein, it is determined at least one described in the acquisition period according to the actual value of discriminant function and predetermined reference function
A parameter, the actual value are closed based on the angle between the electric axis of identified heart and the instantaneous vector of the vectorcardigram
System, the fixed threshold of the actual value of the predetermined reference function based on the discriminant function.
In order to determine at least one parameter described in the acquisition period, depending on human or animal's object interested
Respiratory state, the step of adjusting at least one in the discriminant function and the predetermined reference function, are run.
Phrase " adjustment at least one of discriminant function and predetermined reference function " as used in this application
Should specifically it be understood, so that the step of adjustment is running in any of discriminant function and predetermined reference function
On, or be running on both discriminant function and predetermined reference function.
Phrase " parameter of acquisition period " as used in this application should be specifically interpreted as the time started, at the end of
Between or acquisition the period duration.It can be relative to the specified thing during the cycle movement of the heart of object of interest
Part, such as relative to the cardiomotility at the peak R- about electrocardiogram, specifically determine parameter.
Phrase " vectorcardigram data " as used in this application should be specifically interpreted as average instantaneous space
The registration of the time course of heart vector.The characteristic loop of the instantaneous vector formed in measurement space is marked as P, QRS and T rail
Mark or ring.
It as known in the art, can be by electrocardiogram in order to which the mistake for reducing at least one parameter of acquisition period determines
Data are filtered to reduce the noise level of ECG data.
The present invention knows respiratory period of the electric axis in human or animal's object interested of physics mandrel and associated heart clearly
Between tilt.In intake period, air-breathing contraction of muscle, diaphragm decline, and thoracic cavity rises.During expiration, air-breathing loosening all muscles,
Diaphragm rises, and thoracic cavity declines.In the vectorcardigram (Fig. 2) of acquisition, depending on the out of phase of breathing, characteristic loop rotation
Turn.Block curve in Fig. 2 refers to the vectorcardigram data during eupnea, wherein by completely putting label inspection
The peak R- of survey.Dashed curve indicates the vectorcardigram data during the extreme situation held one's breath, and holds one's breath in magnetic resonance imaging stream
During journey frequent occurrence.
It can determine the breath state of human or animal's object interested according to the signal of Conventional ventilators, or for example it can be with
After ordering people's object interested to be held one's breath, confirmed by medical personnel located.
By adjusting at least one of discriminant function and predetermined reference function, acquired in the period extremely when determining
When a few parameter, it can be considered that the inclination of the instantaneous electric axis of the heart about determining electric mandrel, to realize that magnetic resonance is believed
Number measurement and the more robust of the cycle movement of the heart of object of interest and reliable synchronous.
One in the advantages of the method be when ensuring satisfied picture quality, can be in shorter period
Execute magnetic resonance measurement.
Another advantage is that the operator of magnetic resonance imaging system perceives higher ease for use, this is because passing through the side
Method reliably detects the peak value high-visible to operator.
Another advantage is the more high-throughput that can guide the magnetic resonance imaging session of per time again.
In another preferred embodiment, the step of adjustment includes electric axis and the vector heart modified in identified heart
The angular dependence between the instantaneous vector of electrograph.It, can when determining at least one parameter of acquisition period by this
Easily consider the inclination of the instantaneous electric axis of heart, and can be realized the measurement of magnetic resonance signal and the cycle movement of heart
Robust with it is reliable synchronous.
If to the angle between the electric axis of identified heart and the instantaneous vector of the vectorcardigram
The modification of relationship includes, will in the case where the transition of object generally called between full suction condition of the gas respiratory state to object
Predetermined quantities are adjusted by the angle that the electric axis of identified heart and the instantaneous vector of the vectorcardigram are formed, then
It can be realized the inclined simple and efficient mode for considering the instantaneous electric axis of heart.
In another embodiment, it is formed by the instantaneous vector of the electric axis of identified heart and the vectorcardigram
Angle be conditioned an amount, the amount be about the identified heart of the parameter determining earlier from the acquisition period electric axis from
Derived from the Angle Position of the instantaneous vector of the vectorcardigram.In this way, by using determining and significant shifting earlier
Position position can easily track the shift position of the electric axis of the heart during breathing.
In another preferred embodiment, method further includes calibration steps, and calibration steps is determining at least the one of the acquisition period
It is performed before a parameter.In calibration steps, as the step of adjusting the discriminant function, according to generally calling in the object
The vectorcardigram data obtained under gas respiratory state and the full suction condition of the object, it is a for the object of interest
Determine to body the predetermined quantities for adjusting angle, electric axis and the vectorcardigram of the angle by identified heart
The instantaneous vector is formed.In this way it is possible to consider be attributed to its variation body structure between different objects
Individual difference, to realize the very accurate of the cycle movement of the measurement result of magnetic resonance signal and the heart of object of interest
Synchronization.
Include in the step of this method is again in another preferred embodiment, adjusts the discriminant function, in generally calling for object
In the case where gas respiratory state to the transition between the full inhalation breathing state of object, change in the range of predetermined quantities
The angle formed by the electric axis of identified heart and the instantaneous vector of the vectorcardigram.In this way, for right
Each state of the breathing of elephant, the robustness that can be realized the measurement result of magnetic resonance signal and the cycle movement of heart are same
Step.
In another aspect of the invention, it provides a kind of for acquiring and the cycle movement of the heart of object of interest
The magnetic resonance imaging system of at least part of image of synchronous human or animal's object interested.
The magnetic resonance imaging system includes: main magnet, is used to generate magnetostatic field；Magnetic gradient coil system, is used for
Generate the gradient magnetic for being added to magnetostatic field；And check space, it is provided to position in the inner object of interest.
The magnetic resonance imaging system further includes control unit, and described control unit is for controlling the magnetic resonance imaging system
The function of system.Described control unit is coupled to synchronization unit, and is configured as by the triggering letter from the synchronization unit
It number synchronizes, to generate the control signal for the magnetic gradient coil system for generating the gradient magnetic.In addition, the control
Unit processed is configured as after receiving the trigger signal, generates multiple sequences, each sequence includes radiofrequency field and magnetic gradient field.
In addition, the magnetic resonance imaging system includes:
Image processing unit is provided for handling magnetic resonance signal collected with total according to the magnetic of the acquisition
Vibration signal determines at least part of image of the object of interest,
Ecg equipment is used to take the measurement result of the ECG data of the heart of the object of interest,
And it is configured as generating vectorcardigram data according to the ECG data, the electric axis including the determination heart, and
Synchronization unit is coupled to the ecg equipment, and is configured for according to the vectorcardigram number
According at least one parameter for the acquisition period for determining collecting magnetic resonance signal, wherein according to the actual value of discriminant function and in advance
Determining reference function determines at least one described parameter of the acquisition period, and the actual value is based in identified heart
Electric axis and the vectorcardigram instantaneous vector between angular dependence, the predetermined reference function is based on described sentencing
The fixed threshold of the actual value of other function.
The synchronization unit is configured as: will indicate the touching of at least one parameter determined by the acquisition period
It signals to provide and arrives described control unit；And the respiratory state of human or animal's object interested is depended on, described in adjustment
At least one of discriminant function and the predetermined reference function.
In still yet another aspect of the present, a kind of software module is provided, for according to disclosed method or combinations thereof
In one described in method, by the measurement result of the magnetic resonance signal acquired by magnetic resonance imaging system and object of interest
The cycle movement of heart is synchronous, wherein step is converted into program code, and said program code can be implemented total in the magnetic
In the memory cell of the synchronization unit for imaging system of shaking, and it can be executed by the processor unit of the synchronization unit.
Detailed description of the invention
These and other aspects of the invention will become apparent according to embodiment as described below, and will refer to down
The embodiment of text description is set forth.Such embodiment does not necessarily mean that full scope of the invention, however therefore, in order to explain
Protection scope of the present invention, with reference to claim and this paper.
In the accompanying drawings:
Fig. 1 is the schematic illustration of the part of the embodiment of magnetic resonance imaging system according to the present invention,
Fig. 2 illustrates the vectorcardigram under the different situations of breathing,
Fig. 3 illustrates the arrangement of the electrode of the ecg equipment of the magnetic resonance imaging system according to Fig. 1,
Fig. 4 illustrates the vectorcardigram with trigger area of the adjusting of first embodiment according to the method for the present invention,
Fig. 5 illustrates the vectorcardigram with trigger area adjusted according to another embodiment of method, and
Fig. 6 illustrates the vectorcardigram with trigger area adjusted according to the another embodiment of method.
Reference signs list
10 magnetic resonance imaging systems
12 MR scanners
14 main magnets
16 check space
18 central axises
20 object of interest
22 magnetic gradient coil systems
24 radio-frequency antennas
26 radio shieldings
28 control units
30 RF transmitter units
32 radio frequency switch units
34 image processing units
36 ecg equipments
38 electrodes
40 synchronization units
42 memory cells
44 processor units
46 software modules
48 electric axis directions
50 instantaneous vectors
52 first trigger areas
54 second trigger areas
56 third trigger areas
58 the 4th trigger areas
60 trigger signals
The angle ε
Specific embodiment
Fig. 1 shows the schematic illustration of the part of the embodiment of magnetic resonance imaging system 10 according to the present invention, described
Magnetic resonance imaging system is used to acquire the magnetic resonance image of the part of human or animal's object 20 interested.Especially, magnetic resonance at
It is configured for acquiring the magnetic resonance image of the heart of human or animal's object 20 interested as system 10.Magnetic resonance imaging system 10
Including the MR scanner 12 with main magnet 14, the main magnet is provided for generating magnetostatic field.Main magnet 14 has
Central bore, the central bore provide the object of interest 20 for surrounding central axis 18, human volunteer, the inspection that be located in it
Look into space 16.For clarity the reason of, has had been left out the conventional platform for being used to support object of interest 20 in Fig. 1.It is substantially quiet
The magnetic field of state defines the axial direction for checking space 16, the axial direction and 18 parallel alignment of central axis.In addition, magnetic resonance at
Picture system 10 includes magnetic gradient coil system 22, and the magnetic gradient coil system, which is provided for generating, is added to magnetostatic field
Gradient magnetic.As known in the art, magnetic gradient coil system 22 is concentrically arranged in the thorax of main magnet 14.
In addition, magnetic resonance imaging system 10 includes the radio-frequency antenna 24 for being designed to whole-body coil, it is provided for
RF magnetic field is applied to during radio-frequency transmissions phase and checks space 16, to motivate the core of object of interest 20.Radio-frequency antenna 24
It is further provided with to receive the magnetic resonance signal from the core being stimulated during radio frequency reception phase.In magnetic resonance imaging system 10
Mode of operation under, radio-frequency transmissions phase and radio frequency reception phase occur in a serial fashion.Radio-frequency antenna 24 has central axis,
Also, it in operational conditions, is concentrically arranged in the thorax of main magnet 14, so that the central axis and magnetic of radio-frequency antenna 24 are total
The central axis 18 for imaging system 10 of shaking is consistent.As it is known in the art, cylindrical metal radio shielding 26 is concentrically arranged
Between magnetic gradient coil system 22 and radio-frequency antenna 24.
Magnetic resonance imaging system 10 further includes control unit 28, and described control unit 2 is provided for controlling magnetic resonance and sweeps
Retouch the function of device 12.In addition, magnetic resonance imaging system 10 includes RF transmitter unit 30, the RF transmitter unit is connected
It is connected to control unit 28 and is controlled by control unit 28.RF transmitter unit 30 was provided as in the radio-frequency transmissions phase phase
Between via radio frequency switch unit 32 radio-frequency power of magnetic resonance radio frequency is fed to radio-frequency antenna 24.In the radio frequency reception phase phase
Between, the magnetic resonance signal from radio-frequency antenna 24 is directed to the image procossing being in control unit 28 by radio frequency switch unit 32
Unit 34.Image processing unit 34 is configured for handling magnetic resonance signal collected, to be believed according to magnetic resonance collected
Number determine object of interest 20 part magnetic resonance image.Many different modifications of the technology are for those skilled in the art
For be well known, and therefore do not need to be described in more detail herein.
In order to acquire object of interest 20 heart magnetic resonance image, magnetic resonance imaging system 10 has been further equipped with electrocardio
Figure equipment 36 and synchronization unit 40.
Ecg equipment 36 is provided for obtaining the measurement result of the ECG data of the heart of object of interest 20, and
And be configured as generating vectorcardigram data according to ECG data, this includes the electric axis of determining heart.For this purpose, electrocardiogram is set
Standby 36 multiple electrodes 38 can be arranged according to orthogonal lead to be disposed at object of interest 20, as shown in Figure 3.In addition, the heart
Electrograph equipment 36 includes for being filtered ECG data to reduce the module of the artifact generated by gradient magnetic.It is appropriate
Means of filtering is known for a person skilled in the art, and therefore should not be described in more detail herein.
Ecg equipment 36 is coupled to synchronization unit 40, and the synchronization unit is configured for according to vectorcardigram number
According to the parameter for the acquisition period for determining collecting magnetic resonance signal, as will be described in further detail below.Synchronization unit 40 is then
It is coupled to control unit 28.Control unit 28 is configured as being synchronized by trigger signal 60, generates gradient to generate to be directed to
The control signal of the magnetic gradient coil system 22 in magnetic field, the trigger signal are provided by synchronization unit 40, and indicate acquisition when
The identified parameter of section.For this purpose, control unit 28 is configured as after receiving trigger signal 60, multiple sequences are generated, each
Sequence includes radiofrequency field and magnetic gradient field.
Hereinafter, a kind of such method is presented in detail: the ginseng of acquisition period is determined according to vectorcardigram data
Number, so as to the week of the heart of the measurement result of magnetic resonance signal and object of interest 20 that will be acquired by magnetic resonance imaging system 10
The movement of phase property synchronizes.
The parameter of acquisition period is determined by synchronization unit 40.For this purpose, synchronization unit 40 have storage unit 42,
Processor unit 44 and software module 46 (Fig. 1), wherein the determination step of method, which is converted into, is embodied in synchronization unit 40
Memory cell 42 in and the program code that can be executed by the processor unit 44 of synchronization unit.
In the first step in the method, such as by using the orthogonal lead being shown in FIG. 3 it is arranged, it is interested to obtain
The measurement result of the ECG data of the heart of object 20.In the next step, then ecg equipment 36 according to electrocardiogram number
According to generation vectorcardigram data (Fig. 2), and determine the electric axis (being referred to as " determining heart electric axis " later) of heart, it is described
Electric axis in vectorcardigram by since vectogram origin and with electric axis direction 48 vector (straight arrows) indicate.
In the next step, by the actual value of 44 computational discrimination function of the processor unit of synchronization unit 40.Discriminant function
Based on the angular dependence between the instantaneous vector 50 of determining heart electric axis and vectorcardigram, and in this particular example
It is defined as the instantaneous vector 50 of vectorcardigram and indicates the dot product of the vector of determining heart electric axis.Therefore, the dot product by
Product below provides: the amplitude of the instantaneous vector 50 of vectorcardigram；Indicate the amplitude of the vector of determining heart electric axis；Angle
The cosine function of ε, the angle ε are formed by the electric axis direction 48 of the heart electric axis determined and the instantaneous vector 50 of vectorcardigram.
Synchronization unit 40 is configured as comparing the actual value of the calculating of discriminant function and predetermined reference function
Compared with the fixed threshold of actual value of the reference function based on discriminant function.In this particular example, predetermined reference
Function is given the 75% of the amplitude peak of discriminant function, wherein in a ring phase of instantaneous vector 50 in vectorcardigram
Between determine amplitude peak.In other embodiments, predetermined reference function can be given the amplitude peak of discriminant function
Another percentage or its can be non-constant, and for example, angle ε can be depended on.
Such case is illustrated in Fig. 4, Fig. 4 shows the vectorcardigram number obtained from the ECG data through filtering
According to.When 75% situation of the amplitude peak of the discriminant function during meeting a ring in instantaneous vector 50, this is usually
The case where being for the compound big peak R- the QRS of electrocardiogram, synchronization unit 40 is configured to provide trigger signal 60
Control unit 28.Solid line circle in Fig. 4 indicates that instantaneous vector 50 must fall into the wherein vector electrocardio to meet above-mentioned condition
First trigger area 52 of figure.
As described above, the trigger signal 60 of 28 origin motor synchronizing unit 40 of control unit synchronizes, and is receiving
The control signal for being directed to magnetic gradient coil system 22 is generated after trigger signal 60, so that it is determined that by the time started relative to the peak R-
The parameter for the acquisition period for magnetic resonance imaging system 10 that value cardiomotility provides.In this way it is assured that
Magnetic resonance image is obtained at the same phase of the cycle movement of the heart of object of interest 20.
Solid line ring in Fig. 4 indicates the activity of the heart of object of interest 20 in the case where normal shallow breathing.In Fig. 4
In dotted line ring indicate the activity of full air-breathing and the heart under respiratory state of holding one's breath in object.It is high-visible from Fig. 4, instantaneous vector
Ring of 50 descriptions except the first trigger area 52 of vectorcardigram, so that situation described above will not be satisfied, and
Synchronization unit 40 does not provide any trigger signal 60 to control unit 28.
In order to ensure the full air-breathing also for object is appropriate synchronous with respiratory state of holding one's breath, synchronization unit 40 is configured
To adjust in discriminant function and predetermined reference function depending on the respiratory state of human or animal's object 20 interested
At least one.
In the first embodiment of method, the step of adjustment includes modifying in determining heart electric axis and vectorcardigram
Angular dependence between instantaneous vector 50.In the feelings for generally calling the transition between full suction condition of the gas respiratory state to object of object
Under condition, the modification to the angular dependence between the instantaneous vector 50 of determining heart electric axis and vectorcardigram includes: will be by true
The angle ε that the electric axis direction 48 of fixed heart electric axis and the instantaneous vector 50 of vectorcardigram are formed adjusts predetermined quantities.
In the first embodiment for the step of adjusting, predetermined quantities are -40 °；That is, by determining heart electric axis and
The angle ε in vectorcardigram that the instantaneous vector 50 of vectorcardigram is formed is reduced 40 °.Digitally, this can be by will be true
The instantaneous vector 50 (in Fig. 4 counterclockwise) of fixed heart electric axis towards vectorcardigram rotates 40 °, and by leaving in advance
Determining reference function is not varied to achieve, this is defined on the second trigger area 54 in vectorcardigram.For rotating the heart
The practice mode of the heart electric axis of dirty determination be will have -40 ° rotation angle Two Dimensional Rotating matrix application to vector electrocardio
Two variables of figure.As being able to recognize that from Fig. 4, the instantaneous vector of vectorcardigram under the full inhalation breathing state of object
50 drop on a large scale in the second trigger area 54 by the vectorcardigram of circle of dotted line instruction, make it possible to ensure that magnetic resonance figure
Picture is appropriate synchronous with the cycle movement of the heart of object of interest 20.
In the second embodiment for the step of adjusting, by 50 shape of instantaneous vector of determining heart electric axis and vectorcardigram
At angle ε be conditioned such amount, i.e., the described amount is the heart about the determination of the parameter determining earlier from the acquisition period
Electric axis is derived from the Angle Position of the instantaneous vector 50 of vectorcardigram.In this embodiment, it is required that data analysis it is higher
Effort usually can track the shifting of the practical electric axis of heart in the near future by the QRS of the tracking electrocardiogram compound peak R-
Position, this realizes that magnetic resonance image is fabulous synchronous with the cycle movement of the heart of object of interest 20.In the vector electrocardio of Fig. 5
In figure, the displacement of the practical electric axis of heart is reflected in continuous moving circle third trigger area 561To 56nIn, this by for pair
The round number of the number of given time is answered to indicate.
In the third embodiment, before the parameter for determining the acquisition period, the method also includes calibration steps, wherein
According to the vectorcardigram data obtained under the full suction condition for generally calling gas respiratory state and object of object, for interested
Object 20, individually to determine for adjusting the angle ε formed by the instantaneous vector 50 of determining heart electric axis and vectorcardigram
Predetermined quantities, used in the step of discriminant function can be adjusted after the calibration.
Table 1 is shown for determining for generally calling between gas respiratory state and the full suction condition of object in individual subject
Each change heart practical electric axis experimental result.Although as a result showing object specific variations, about 30 °
Average value has been obtained, and can be used for adjusting by 50 shape of instantaneous vector of determining heart electric axis and vectorcardigram
At angle ε.
By other experimental datas, have been acknowledged the sum obtained during eupnea in the full suction with the object held one's breath
The amplitude of the reference instantaneous vector of the vectorcardigram obtained under gaseity does not significantly change, so that for many situations, in advance
Determining reference function can be still changed.
Table 1
However, predetermined reference function necessary can be adjusted in the case where certain heart diseases, or for same
The more high precision of step finely tunes trigger area 52,54,56 in the case where requiring.
In the fourth embodiment of method, adjust discriminant function the step of include object generally call gas respiratory state to pair
In the case where transition between the full inhalation breathing state of elephant, variation is by determining cardiac electric in the range of predetermined quantities
The angle ε that the instantaneous vector 50 of axis and vectorcardigram is formed.In the vectorcardigram of Fig. 6, this is justified by trigger area from initial
Reflect to the extension of the 4th trigger area 58, the 4th trigger area is by by initially justifying about by vectorcardigram original
It puts and is indicated perpendicular to the area of the rotation generation of the axis of its plane.Widened 4th trigger area 58 ensures from vectorcardigram
Reliable determination of the data at least one parameter of acquisition period.
In principle, disclosed invention can also be applied to the magnetic resonance imaging system of any other such type, that is,
Inspection area is provided in magnetostatic field, for example, open C- shape magnetic resonance imaging system, and be equipped with auxiliary as described herein
Unit and equipment are helped, the auxiliary unit and equipment are such as required the embodiment or combinations thereof to execute disclosed method.
It is such to illustrate and retouch although illustrating and describing the present invention in detail in the drawings and the preceding description
Stating will be considered as illustrative or exemplary, and not restrictive；The present invention is not limited to the disclosed embodiments.Pass through research
Attached drawing, disclosure and claims, those skilled in the art when practicing the claimed invention it will be appreciated that
With realization other variants of the disclosed embodiments.In the claims, one word of " comprising " is not excluded for other elements or step,
And word "a" or "an" is not excluded for multiple.Although describing certain measures in mutually different dependent claims,
But this does not indicate that the combination that these measures cannot be used to advantage.Any appended drawing reference in claims should not be solved
It reads as the limitation to range.
Claims (8)
1. it is a kind of by means of magnetic resonance to the human or animal's object (20) interested being located in magnetostatic field at least partly into
The method of row imaging, which comprises
Obtain the measurement result of the ECG data of the heart of object of interest (20)；
Vectorcardigram data, the electric axis including the determination heart are generated according to the ECG data；
Determine at least one parameter of the acquisition period of collecting magnetic resonance signal, according to the vectorcardigram data to incite somebody to action
The measurement result of magnetic resonance signal is synchronous with the cycle movement of the heart of the object of interest (20)；Wherein, pass through
The actual value and predetermined reference function that compare discriminant function determine at least one described parameter of acquisition period, described to sentence
Other function is described based on the angular dependence between the electric axis of identified heart and the instantaneous vector (50) of the vectorcardigram
The fixed threshold of the actual value of the predetermined reference function based on the discriminant function, wherein in order to be adopted described in determination
Collect at least one described parameter of period, depends on the respiratory state of human or animal's object (20) interested, execute adjustment
The step of at least one in the discriminant function and the predetermined reference function.
2. the step of the method for claim 1, wherein adjusting include modify electric axis in identified heart with it is described
The angular dependence between the instantaneous vector (50) of vectorcardigram.
3. method according to claim 2, wherein to described in the electric axis of identified heart and the vectorcardigram
The modification of the angular dependence between instantaneous vector (50) includes: to generally call the full suction of gas respiratory state to object in object
It, will be by the instantaneous vector of the electric axis of identified heart and the vectorcardigram in the case where transition between gaseity
(50) angle (ε) formed adjusts predetermined quantities.
4. the method as described in any one of claim 1-3, wherein electric axis and the vector heart by identified heart
The angle (ε) that the instantaneous vector (50) of electrograph is formed is conditioned an amount, and the amount is about true earlier from the acquisition period
The electric axis of the identified heart of fixed parameter is derived from the Angle Position of the instantaneous vector (50) of the vectorcardigram.
5. the method as described in any one of claim 1-3 is determining at least one parameter described in the acquisition period
Before, further include the steps that calibration, wherein as the step of adjusting the discriminant function, generally call gas according in the object
The vectorcardigram data obtained under respiratory state and the full suction condition of the object, for the object of interest (20),
Individually determine the predetermined quantities for adjusting angle (ε), electric axis and the vector heart of the angle by identified heart
The instantaneous vector (50) formation of electrograph.
6. the method as described in any one of claim 1-3, wherein the step of adjusting the discriminant function includes: right
Elephant generally call gas respiratory state to the transition between the full inhalation breathing state of object in the case where, in the model of predetermined quantities
Enclose the interior angle (ε) for changing and being formed by the electric axis of identified heart and the instantaneous vector (50) of the vectorcardigram.
7. one kind is for acquiring the interested human or animal object synchronous with the cycle movement of heart of object of interest (20)
(20) magnetic resonance imaging system (10) of at least part of image, comprising:
Main magnet (14), is used to generate magnetostatic field；
Magnetic gradient coil system (22) is used to generate the gradient magnetic for being added to the magnetostatic field；
It checks space (16), is provided so that the object of interest (20) to be positioned inside it；
Control unit (28), is used to control the function of the magnetic resonance imaging system (10), wherein described control unit
(28) synchronization unit (40) are coupled to, and are configured as by the trigger signal (60) from the synchronization unit (40) Lai same
Step, it is described to generate the control signal for the magnetic gradient coil system (22) for generating the gradient magnetic, and wherein
Control unit (28) is configured as after receiving the trigger signal (60), generates multiple sequences, each sequence includes radiofrequency field
And magnetic gradient field；
Image processing unit (34) is provided for handling magnetic resonance signal collected with total according to the magnetic of the acquisition
Vibration signal determines at least part of image of the object of interest (20)；
Ecg equipment (36) is used to obtain the measurement of the ECG data of the heart of the object of interest (20)
As a result, and being configured as generating vectorcardigram data, the electric axis including the determination heart according to the ECG data；
Synchronization unit (40) is coupled to the ecg equipment (36), and is configured for according to the vector electrocardio
Diagram data determines at least one parameter of the acquisition period of collecting magnetic resonance signal, wherein by comparing the reality of discriminant function
Value and predetermined reference function determine at least one described parameter of the acquisition period, and the discriminant function is based in institute
Angular dependence between the electric axis of determining heart and the instantaneous vector (50) of the vectorcardigram, the predetermined reference
The fixed threshold of the actual value of the function based on the discriminant function, wherein the synchronization unit (40) is configured as to refer to
Show that the trigger signal (60) of at least one identified parameter of the acquisition period is provided to described control unit (28)；
And
Wherein, the synchronization unit (40) is configured as, and depends on the respiratory state of human or animal's object (20) interested,
Adjust at least one of the discriminant function and the predetermined reference function.
8. a kind of storage medium, including code, the code is used for according to side according to any one of claims 1 to 6
Method, will be by the week of the heart of the measurement result and object of interest (20) for the magnetic resonance signal that magnetic resonance imaging system (10) acquire
The movement of phase property synchronizes, wherein the code can implement depositing in synchronization unit (40) of the magnetic resonance imaging system (10)
In storage unit (42), and it can be executed by the processor unit (44) of the synchronization unit (40).
Applications Claiming Priority (3)
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| EP13179571.8 | 2013-08-07 | ||
| EP13179571 | 2013-08-07 | ||
| PCT/EP2014/066950 WO2015018879A1 (en) | 2013-08-07 | 2014-08-07 | Improved ecg-based triggering for magnetic resonance imaging |
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| Publication Number | Publication Date |
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| CN105452893A CN105452893A (en) | 2016-03-30 |
| CN105452893B true CN105452893B (en) | 2019-08-06 |
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| CN201480044173.1A Expired - Fee Related CN105452893B (en) | 2013-08-07 | 2014-08-07 | The improved triggering based on ECG for magnetic resonance imaging |
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| EP (1) | EP3030918B1 (en) |
| JP (1) | JP2016528982A (en) |
| CN (1) | CN105452893B (en) |
| WO (1) | WO2015018879A1 (en) |
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| EP3080635A1 (en) * | 2013-12-10 | 2016-10-19 | Koninklijke Philips N.V. | Calculating mri rf coil sensitivities using interpolation into an enlarged field of view |
| DE102018214636A1 (en) * | 2018-08-29 | 2020-03-05 | Siemens Healthcare Gmbh | Method for generating a magnetic resonance image, computer program, data storage and magnetic resonance system |
| CN109507622B (en) * | 2018-11-16 | 2021-08-17 | 上海联影医疗科技股份有限公司 | Magnetic resonance imaging method and system |
| CN110755076B (en) | 2019-11-01 | 2023-08-11 | 上海联影医疗科技股份有限公司 | Image acquisition method, device, equipment and medium of magnetic resonance scanner |
| CN112932440B (en) * | 2019-11-25 | 2023-07-11 | 上海联影医疗科技股份有限公司 | Flow velocity encoding method, magnetic resonance imaging method and magnetic resonance imaging system |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5987348A (en) * | 1997-07-23 | 1999-11-16 | Philips Electronics North America Corporation | ECG triggered MR imaging method and apparatus |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2464737A1 (en) * | 2001-11-02 | 2003-05-15 | Vincent B. Ho | Cardiac gating method and system |
| US6798199B2 (en) * | 2003-02-06 | 2004-09-28 | Siemens Medical Solutions Usa, Inc. | Method for synchronizing magnetic resonance imaging data to body motion |
| US7738943B2 (en) | 2004-11-19 | 2010-06-15 | General Electric Company | System and method for identifying periodic motion complexes for MR imaging triggering |
| DE102005049862A1 (en) * | 2005-10-18 | 2007-04-26 | Siemens Ag | Movement correction method for use during imaging heart, involves combining recorded pictures with one another to generate combined image data record, where calculated variation is taken into account when combining pictures |
| DE102009055961B4 (en) * | 2009-11-27 | 2018-10-18 | Siemens Healthcare Gmbh | Method for detecting a respiratory movement of an examination subject of corresponding signal data by means of magnetic resonance |
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2014
- 2014-08-07 CN CN201480044173.1A patent/CN105452893B/en not_active Expired - Fee Related
- 2014-08-07 US US14/909,483 patent/US10261160B2/en active Active
- 2014-08-07 EP EP14750455.9A patent/EP3030918B1/en active Active
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- 2014-08-07 WO PCT/EP2014/066950 patent/WO2015018879A1/en active Application Filing
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5987348A (en) * | 1997-07-23 | 1999-11-16 | Philips Electronics North America Corporation | ECG triggered MR imaging method and apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2016528982A (en) | 2016-09-23 |
| EP3030918A1 (en) | 2016-06-15 |
| US10261160B2 (en) | 2019-04-16 |
| WO2015018879A1 (en) | 2015-02-12 |
| US20160202337A1 (en) | 2016-07-14 |
| EP3030918B1 (en) | 2022-11-16 |
| CN105452893A (en) | 2016-03-30 |
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